Office of Water

Office Science and

Technology EPA 820-D- 14 -0 62

May 2014



# Draft Update of Human Health

Ambient Water Quality Criteria:

Tetrachloroethylene

127

- 18 -4EPA 820 -D- 14 -0 62

May 2014



# Update of Human Health

Ambient Water Quality Criteria:

Tetrachloroethylene

127

- 18 -4

Draft

Office of Science and Technology

Office of Water

U.S. Environmental Protection Agency

Washington, DC 20460Tetrachloroethylene 127

- 18 -4

Table of Contents

Introduction: Plan and Scope of Update

Problem Formulation

Criteria Formulas- Analysis Plan

Exposure Factors

Body Weight

Drinking Water Intake

Fish Consumption Rate

Bioaccumulation Factor

Hazard Identification and Dose Response: Cancer Slope Factor

Criteria Derivation- Analysis

Criteria Characterization

Chemical Name / Synonyms

References

Introduction: Plan and Scope of Update

Human health ambient water quality criteria (AWQC) are numeric values for pollutant

concentrations in ambient waters that the U.S. Environmental Protection Agency (EPA)

consider s to be protective of human health. EPA periodically revises water quality criteria to

ensure that they reflect the latest scientific knowledge

. The current revisions of the criteria for

tetrachloroethylene, contained in this document, incorporate updated information regarding

cancer risk, body weight, drinking water intake, fish consumption rate, and bioaccumulation.

Updated cancer risk information for tetrachloroethylene is identified in E ́!͛ν ͸͕͕Ί̽͋ Ϊ͕ ·͋ν̯͋ι̽·

and Development Integrated Risk Information System (IRIS) 2012 toxicology assessment

(USEPA, 2012c)  ̈́ Εζ͇̯χ͇͋ ̼Ϊ͇Θ Ϯ͋Ίͽ·χ ̯Σ͇ ͇ιΊΣΙΊΣͽ Ϯ̯χ͋ι ΊΣχ̯Ι͋ ͇̯χ̯ ̯ι͋ Ί͇͋ΣχΊ͕Ί͇͋ ΊΣ E ́!͛ν

·EϳζΪνϢι͋ F̯̽χΪιν H̯Σ͇̼ΪΪΙ ́ 2011 E͇ΊχΊΪΣ͛ (Ε΋E ́!΂ 2011) ̈́ The bioaccumulation factor data is

updated usin ͽ E ́!͛ν EνχΊ΢̯χΊΪΣ  ́ιΪͽι̯΢ ͜Σχ͋ι͕̯̽͋ (E ́͜) ΋ϢΊχ͋ ΢Ϊ͇͋ΜΊΣͽ ζιΪͽι̯΢ (Ε΋E ́!΂

2012a). The overall fish consumption rate and trophic level breakdowns are updated using

E ́!͛ν ·EνχΊ΢̯χ͇͋ FΊν· ΪΣνϢ΢ζχΊΪΣ ·̯χ͋ν ͕Ϊι χ·͋ Ε ̈́΋ ̈́  ́ΪζϢΜ̯χΊΪΣ ̯Σ͇ ΋͋Μ͋̽χ͇͋ ΋Ϣ̼ζΪζϢΜ̯χΊΪΣν

(NHANES 2003- 2010)͛ (Ε΋E ́!΂ 2014) . Unless otherwise specified, all sources of information

used in this update are from peer reviewed sources.

Note that the term "water quality criteria" can carry one of two possible meanings,

depending on the section of the Clean Water Act (CWA) associated with the particular criteria

̯χ ΊννϢ͋ ̈́ ͞Ρ̯χ͋ι θϢ̯ΜΊχΘ ̽ιΊχ͋ιΊ̯͟ ΢̯Θ ι͕͋͋ι χΪ Σ̯χΊΪΣ̯Μ Ϯ̯χ͋ι θϢ̯ΜΊχΘ ̽ιΊχ͋ιΊ a recommendations

issued under CWA § 304 ̈́ ͞Ρ̯χ͋ι θϢ̯ΜΊχΘ ̽ιΊχ͋ιΊ̯͟ ΢̯Θ ̯ΜνΪ ι͕͋͋ι χΪ Ϯ̯χ͋ι θϢ̯ΜΊχΘ ̽ιΊχ͋ιΊ̯

components of water quality standards adopted by states, territories, or authorized tribes

under CWA § 303.

National ambient water quality criteria recommendations for human health are issued

by the EPA under CWA § 304. They are based on the latest scientific information on the

relationship between the effects of a constituent concentration and human health. Protective

1Tetrachloroethylene 127

- 18 -4

assumptions are made regarding the potential human exposure intakes. These criteria do not

reflect consideration of non-human health endpoints or economic impacts. Nor do they reflect

the technological feasibility of meeting the chemical concentrations in ambient water. National

ambient water quality criteria recommendations for human health are not automatically

incorporated into water quality standards adopted by states, territories, or authorized tribes.

Rather, they provide scientific information to states, territories and authorized tribes to assist

them in adopting ambient water quality criteria for human health in water quality standards

that meet CWA requirements. National ambient water quality criteria recommendations for

human health are not regulations themselves and they do not impose legally binding

requirements on EPA, states, territories, authorized tribes, or the public. States, territories, and

authorized tribes have the discretion to adopt, where appropriate, other scientifically

defe ΣνΊ̼Μ͋ Ϯ̯χ͋ι θϢ̯ΜΊχΘ ̽ιΊχ͋ιΊ̯ χ·̯χ ͇Ί͕͕͋ι ͕ιΪ΢ E ́!͛ν Σ̯χΊΪΣ̯Μ ̯΢̼Ί͋Σχ ι͋̽Ϊ΢΢͋Σ͇͇͋ ̽ιΊχ͋ιΊ̯

for human health.

Ambient water quality criteria components of water quality standards are generally

adopted by the states, territories, and authorized tribes themselves, under § 303(c)(2). (In

certain circumstances EPA also may promulgate this type of criterion itself, pursuant to

§303(c)(4)). State ambient water quality criteria for human health represent a quality of water

that sufficiently protects human health to support a designated use of the state, territory, or

authorized tribe. Such criteria may be expressed in terms of constituent concentrations, levels,

or narrative statements. Once ambient water quality criteria for human health are adopted by a

state, territory, or authorized tribe into their water quality standards, they provide a basis for

controlling discharges or releases of pollutants, for developing permit limits, assessing waters,

and developing total maximum daily loads (TMDLs) for waters that do not meet the water

quality standard. Ambient water quality criteria for human health have a regulatory impact

once they have been adopted into water quality standards by the state, territory, or authorized

tribe under § 303(c)(2) (or alternatively issued by EPA pursuant to § 303(c)(4)).

The water quality criteria at issue in this document are national ambient water quality

criteria recommendations for human health issued under CWA § 304. Unless expressly

ΊΣ͇Ί̯̽χ͇͋ Ϊχ·͋ιϮΊν͋΂ ̯ΜΜ ι͕͋͋ι͋Σ̽͋ν χΪ ̽͞ιΊχ͋ιΊ̯΂͟ ͞Ϯ̯χ͋ι θϢ̯ΜΊχΘ ̽ιΊχ͋ιΊ̯΂͟ ̯͞΢̼Ί͋Σχ Ϯ̯χ͋ι θϢ̯ΜΊχΘ

̽ιΊχ͋ιΊ̯ (!ΡΆ) ι͋̽Ϊ΢΢͋Σ͇̯χΊΪΣν΂͟ Ϊι νΊ΢ΊΜ̯ι ϭ̯ιΊ̯Σχν χ·͋ι͋Ϊ͕΂ ̯ι͋ ι͕͋͋ι͋Σ̽͋ν χΪ Σ̯χΊΪΣ̯Μ

ambient water quality criteria recommendations for human health.

Problem Fo rmulation

Problem formulation provides a strategic framework for water quality criteria

development by focusing on the most relevant endpoints and increasing the transparency of

the effects assessment process. The structure of this criteria document is consistent with U.S.

E ́!͛ν ·Fι̯΢͋ϮΪιΙ ͕Ϊι HϢ΢̯Σ H̯͋Μχ· ·ΊνΙ !νν͋νν΢͋Σχ χΪ ͜Σ͕Ϊι΢ D͋̽ΊνΊΪΣ ͱ̯ΙΊΣͽ͛ ( USEPA,

2012b).

In the development of AWQC, EPA currently follows the deterministic assessment

methodology outlined in E ́!͛ν · Methodology for Deriving Ambient Water Quality Criteria for

2Tetrachloroethylene 127

- 18 -4

the Protection of Human Health (2000) ͛ (USEPA, 2000), hereafter known as the 2000

Methodology. For the development of criteria for carcinogens that express a non-threshold,

linear dose response, the 2000 Methodology takes into consideration exposure factors (body

weight, drinking water intake, fish consumption, and bioaccumulation), the increased cancer

risk due to exposure to the pollutant, and a 10 -6 (or 1 in 1,000,000) risk level for the general

population. The 10 -6 risk level utilized in the derivation of the AWQC represents the water

̽ΪΣ̽͋Σχι̯χΊΪΣ χ·̯χ ϮΪϢΜ͇ ̼͋ ͋ϳζ͋̽χ͇͋ χΪ ΊΣ̽ι̯͋ν͋ ̯Σ ΊΣ͇ΊϭΊ͇Ϣ̯Μ͛ν ΜΊ͕͋χΊ΢͋ cancer risk from

exposure to the particular pollutant by no more than one chance in one million, regardless of

the additional lifetime cancer risk due to exposure, if any, to that particular substance from

other sources. States and authorized tribes may consider adjusting exposure assumptions and

related model inputs according to guidance in the 2000 Methodology, to assure that

subpopulations are adequately protected if data are available.

Criteria Formulas- Analysis Plan

The following formulas are used to develop E ́!͛ν Ρ! ΋͋̽χΊΪΣ 304(̯) human health

ambient water quality criteria. EPA develops criteria for ambient waters typically considering

two routes of exposure. The first formula can be used to derive a human health criterion that

assumes exposure through both the consumption of water and the consumption of aquatic

organisms. The second formula can be used to derive a criterion that assumes exposur e

through the consumption of aquatic organisms, but not water. The use of one criterion over the

other depends on the designated use of the water bodies in question (i.e. drinking water source

and/or fishable waters).

EPA recommends inclusion of the drinking water exposure pathway for ambient surface

waters where drinking water is a designated use for the following reasons: (1) Drinking water is

a designated use for surface waters under the CWA, and therefore, criteria are needed to

assure that this designated use can be protected and maintained. (2) Although rare, there are

some public water supplies that provide drinking water from surface water sources without

treatment. (3) Even among the majority of water supplies that do treat surface waters, existin g

treatments may not necessarily be effective for reducing levels of particular contaminants. (4)

͜Σ ̽ΪΣνΊ͇͋ι̯χΊΪΣ Ϊ͕ χ·͋ !ͽ͋Σ̽Θ͛ν ͽΪ̯Μν Ϊ͕ ζΪΜΜϢχΊΪΣ ζι͋ϭ͋ΣχΊΪΣ΂ ̯΢̼Ί͋Σχ Ϯ̯χ͋ιν ν·ΪϢΜ͇ ΣΪχ ̼͋

contaminated to a level where the burden of achieving health objectives is shifted away from

those responsible for pollutant discharges and placed on downstream users to bear the costs of

upgraded or supplemental water treatment (USEPA, 2000).

EPA recommends the organism only criterion in those cases where the designated uses

of a water body include only supporting fishable uses under Section 101(a) of the CWA, and

thus, fish or shellfish for human consumption, but not as a drinking water supply source (e.g.,

non-potable estuarine waters) (USEPA, 2000).

3(Eq.1)

( Eq. 2) Tetrachloroethylene 127

- 18 -4

The formulas for deriving the criteria values are as follows (USEPA, 2000):

For consumption of water and organisms:

AWQC (μg/L) = [10 -6 * / CSF (kg·d/mg)] × BW (kg) × 1000 (μg/mg) †

4 DI (L/d) + ∑ (F · Ί (Ιͽ / ͇) ∓ !F Ί (ͫ Ιͽ)) Ί 2

Fo r consumption of organisms only:

AWQC (μg/L) = [10 -6 * / CSF (kg·d/mg)] × BW (kg) × 1000 (μg/mg) †

4 ∑ (F · Ί (Ιͽ / ͇) ∓ !F Ί (ͫ Ιͽ))

Ί 2

Where:

AWQC = ambient water qual ity criteria (at the 10 -6 risk level)

CSF = cancer slope factor

BW = body weight

DI = drinking water intake

∑ 4 νϢ΢΢̯χΊΪΣ Ϊ͕ ϭ̯ΜϢ͋ν ͕Ϊι ̯θϢ̯χΊ̽ χιΪζ·Ί̽ Μ͋ϭ͋Μν (Αͫ) Ϯ·͋ι͋ χ·͋ Μ͋χχ͋ι ͞Ί͟ νχ̯Σ͇ν ͕Ϊι χ·͋

i=2 trophic levels to be considered, starting with TL 2 and proceeding to TL 4

FCR i = fish consumption rate for aquatic trophic levels 2, 3, and 4

BAF i = bioaccumulation factor for aquatic trophic levels 2, 3, and 4

* 10 -6 or 1 in 1,000,000 risk level for the general population

† 1000 μg/mg is used to convert the units of mass into micrograms from milligrams.

4 T he follo wing s ect i o n s i d en t i fy ea ch of the components of the formulas for the human

health ambient water quality c riteria and provide reference sources, previously u sed values

when available, and the values to be used in the updated criteria.

Exposure Factors:

Body Weight

The up dated recommended body weight (BW) is 80 kg which represents the mean

weight for adults 21 years of age and older. Α·Ίν ι͋̽Ϊ΢΢͋Σ͇̯χΊΪΣ Ίν ͕ΪϢΣ͇ ΊΣ E ́!͛ν ·EϳζΪνϢι͋

F̯̽χΪιν H̯Σ͇̼ΪΪΙ ́ 2011 E͇ΊχΊΪΣ͛ in Chapter 8. It was based on data derived from the National

Health and Nutrition Examination Survey (NHANES) 1999

− 2006 (USEPA, 2011). This body

weight replac es the recommended standard weight for adults of 70 kg that was described in

the 2000 Methodology which was approximated from the mean body w eight of adults from the

National Health and Nutrition Examination Survey (NHANES) III database (1988-1994) and a

1989 study b y t he National Cancer Institute (USEPA, 2000).Tetrachloroethylene 127

- 18 -4

Drinking Water Intake

The updated drinking water intake (DI) is 3 L/day, rounded from 3.091 L/day for

consumer-only estimates of direct and indirect water ingestion based on NHANES 2003-2006

data for all sources of water at the 90 th ζ͋ι̽͋ΣχΊΜ͋ ͕Ϊι ̯͇ϢΜχν (≥2 1 years of age) (USEPA, 2011).

Direct water is defined as water ingested directly as a beverage (from all sources); indirect

water is defined as water added in the preparation of food or beverages, not including indirect

consumption of bottled water. This recommended value Ίν ͕ΪϢΣ͇ ΊΣ E ́!͛ν ·EϳζΪνϢι͋ F̯̽χΪιν

H̯Σ͇̼ΪΪΙ ́ 2011 E͇ΊχΊΪΣ͛ in Table 3- 36. It replaces the drinking water intake standard of 2 L/day

described in the 2000 Methodology which represented the 86 th percentile for adults 20 years

and older in χ·͋ Ε΋ D͋ζ̯ιχ΢͋Σχ Ϊ͕ !ͽιΊ̽ϢΜχϢι͋͛ν 1994 -96 Continuing Survey of Food Intake by

Individuals (CSFII) analysis or the 88 th percentile of adults in the National Cancer Institute study

of the 1977-78 Nationwide Food Consumption Survey (USEPA, 2000).

Fish Consumption Rate

The updated fish consumption rate (FCR) for the general adult population is 22

grams/day (0.022 kg/day) (USEPA, 2014: see Table 9a ). It represents the 90 th percentile per

capita consumption rate of freshwater and estuarine fish for the U.S. adult population 21 years

of age and older based on the Centers for Disease Control and Prevention (CDC) National

Health and Nutrition Examination Surveys (NHANES) conducted from 2003-2010. It replaces the

FCR default of 17.5 grams/day, which represented an estimate of the 90th percentile per capita

consumption rate of freshwater and estuarine fish for the U.S. adult population based on the

Ε ̈́΋ ̈́ D͋ζ̯ιχ΢͋Σχ Ϊ͕ !ͽιΊ̽ϢΜχϢι͋͛ν (Ε΋D!͛ν) ΪΣχΊΣϢΊΣͽ ΋Ϣιϭ͋Θ Ϊ͕ FΪΪ͇ ͜Σχ̯Ι͋ ̼Θ ͜Σ͇ΊϭΊ͇Ϣ̯Μν

(CSFII) 1994-96 data (USEPA, 2002a).

As recommended in the 2000 Methodology, this update to the criteria distinguishes a

trophic level (TL) breakdown of the fish consumption rate to provide a better representation of

dietary exposure to fish at multiple trophic levels. An Ϊιͽ̯ΣΊν΢͛ν χιΪζ·Ί̽ ζΪνΊχΊΪΣ ΊΣ χ·͋ ̯θϢ̯χΊ̽

food web can have an important effect on the magnitude of bioaccumulation of certain

chemicals. The trophic levels are numbered 2, 3, and 4 and account for different categories of

fish and shellfish species based on their position in the aquatic food web. TL2 accounts for

benthic filter feeders, TL3 accounts for forage fish, and TL4 accounts for predatory fish.

In order to derive the trophic level breakdown of the 22 grams/day freshwater and

estuarine FCR, the trophic level specific freshwater and estuarine FCR data sets for adults 21

years of age and older were identified (USEPA, 2014: see Tables 16a, 17a, and 18a ). In each

χιΪζ·Ί̽ Μ͋ϭ͋Μ νζ͋̽Ί͕Ί̽ ͇̯χ̯ ν͋χ΂ χ·͋ ι̯χΊΪ Ϊ͕ χ·̯χ χιΪζ·Ί̽ Μ͋ϭ͋Μ͛ν 90 th percentile FCR compared to

the summation of all three trophic level specific 90 th percentile FCRs was applied to the 22

grams/day FCR used in this update. The trophic level ratios were calculated as follows: TL ratio

= 90 th percentile FCR for the TL divided by the sum of the 90 th percentile FCRs for all TLs. TL2 =

7.6/21.3 = 0.3568 (35.68%), TL3 = 8.6/21.3 = 0.4038 (40.38%), and TL4 = 5.1/21.3 = 0.2394

(23.94%). Applying these ratios to the updated FCR of 22 grams/day result in trophic level

breakdowns of TL2 = 8 grams/day (0.008 kg/day); TL3 = 9 grams/day (0.009 kg/day); and TL4 = 5

5Tetrachloroethylene 127

- 18 -4

grams/day (0.005 kg/day). These resulting trophic level FCRs are well within the confidence

ΊΣχ͋ιϭ̯Μν ͕Ϊι ̯͋̽· Ϊ͕ χ·͋ χιΪζ·Ί̽ Μ͋ϭ͋Μ νζ͋̽Ί͕Ί̽ ͇ΊνχιΊ̼ϢχΊΪΣν͛ 90 th percentiles and add to the total

of 22 grams/day (USEPA, 2014).

Bioaccumulation Factor

Several attributes of the bioaccumulation process are important to understand when

deriving national BAFs for use in setting national 304(a) criteria. First, the term

̼͞ΊΪ̯̽̽Ϣ΢ϢΜ̯χΊΪΣ͟ ι͕͋͋ιν χΪ χ·͋ Ϣζχ̯Ι͋ ̯Σ͇ ι͋χ͋ΣχΊΪΣ Ϊ͕ ̯ ̽·͋΢Ί̯̽Μ ̼Θ ̯Σ ̯θϢ̯χΊ̽ Ϊιͽ̯ΣΊν΢

from ̯ΜΜ νϢιιΪϢΣ͇ΊΣͽ ΢͇͋Ί̯ (͋ ̈́ͽ ̈́΂ Ϯ̯χ͋ι΂ ͕ΪΪ͇΂ ν͇͋Ί΢͋Σχ) ̈́ Α·͋ χ͋ι΢ ̼͞ΊΪ̽ΪΣ̽͋Σχι̯χΊΪΣ͟ ι͕͋͋ιν χΪ

the uptake and retention of a chemical by an aquatic organism from water only. For some

chemicals (particularly those that are highly persistent and hydrophobic), the magnitude of

bioaccumulation by aquatic organisms can be substantially greater than the magnitude of

bioconcentration. Thus, an assessment of bioconcentration alone may underestimate the

extent of accumulation in ̯θϢ̯χΊ̽ ̼ΊΪχ̯ ͕Ϊι χ·͋ν͋ ̽·͋΢Ί̯̽Μν ̈́ !̽̽Ϊι͇ΊΣͽΜΘ΂ E ́!͛ν ͽϢΊ͇͋ΜΊΣ͋ν

presented in the 2000 Methodology emphasize the measurement or estimation of chemical

bioaccumulation by aquatic organisms (USEPA, 2000).

Α·͋ ̼ΊΪ̯̽̽Ϣ΢ϢΜ̯χΊΪΣ ͕̯̽χΪιν (!F) ·̯ϭ͋ ̼͋͋Σ ͋νχΊ΢̯χ͇͋ ϢνΊΣͽ E ́!͛ν EνχΊ΢̯χΊΪΣ  ́ιΪͽι̯΢

͜Σχ͋ι͕̯̽͋ (E ́͜) ΋ϢΊχ͋ (Ε΋E ́!΂ 2012̯) ̈́ Α·͋ F!FTM ζιΪͽι̯΢ ϮΊχ·ΊΣ E ́͜ ΋ϢΊχ͋ estimates fish

bioaccumulation factors using octanol-water partition coefficients (K OW ) and biotransformation

data from a model designed by Arnot and Gobas (2003)

. The model includes mechanistic

processes for bioaccumulation such as chemical uptake from the water at the gill surface and

from the diet, chemical elimination at the gill surface, fecal egestion, growth dilution and

metabolic biotransformation. Other processes included in the calculations are bioavailability in

the water column (only the freely dissolved fraction can bioconcentrate) and absorption

efficiencies at the gill and in the gastrointestinal tract. The model requires the octanol-water

partition coefficient (K OW ) of the chemical and the normalized whole-body metabolic

biotransformation rate constant as input parameters to predict BAF values. Model predictions

may be highly uncertain for chemicals that have estimated log K OW values > 9. The model is not

recommended at this time for chemicals that appreciably ionize, for pigments and dyes, or for

perfluorinated substances (USEPA, 2012a).

For tetrachloroethylene, BAFs have been estimated using the EPI Suite model (USEPA,

2012a) as described above for trophic levels 2, 3, and 4. The estimated lower (TL2), mid (TL3),

and upper (TL4) trophic level BAFs for tetrachloroethylene (log K OW = 3.40) are 54.22 L/kg,

52.97 L/kg, and 46.04 L/kg wet-weight, respectively. These estimated BAFs replace the

bioconcentration factor (BCF) of 30.6 L/kg used in the 2002 criteria derivations, which was

calculated from a measured steady-state bioconcentration factor from a study using bluegills

and represented all trophic levels (USEPA, 1980).

6Tetrachloroethylene 127

- 18 -4

Hazard Identification and Dose Response: Cancer Slope Factor

Tetrachloroethylene Ίν ̽·̯ι̯̽χ͋ιΊΣ͇͋ ̯ν ͞ΜΊΙ͋ΜΘ χΪ ̼͋ ̯̽ι̽ΊΣΪͽ͋ΣΊ̽ χΪ ·Ϣ΢̯Σν͟ ͕ΪΜΜΪϮΊΣͽ

the 2005 EPA Guidelines for Carcinogen Risk Assessment (USEPA, 2005; USEPA, 201 2c ).

The cancer slope factor (CSF) is an upper bound, approximating a 95% confidence limit,

on the increased cancer risk from a lifetime oral exposure to an agent. The previously used CSF

for tetrachloroethylene was 3.98 × 10 – 2 per mg/kg·day (USEPA, 1980 ). ͜Σ 2012΂ E ́!͛ν ͸͕͕Ί̽͋ Ϊ͕

Research and Development Integrated Risk Information System (IRIS) updated the toxicology

assessment for tetrachloroethylene. That assessment (USEPA, 2012c), which has been subject

to extensive internal and external peer review, provides the basis for the updated CSF of 2×10 – 3

per mg/kg·day (0.002 per mg/kg·day) used to update the AWQC.

The principle study by the Japan Industrial Safety Association (JISA, 1993) chosen to

calculate the cancer slope factor for tetrachloroethylene was based on development of

hepatocellular adenomas or carcinomas in male Crj:BDF1 mice through inhalation exposure to

tetrachloroethylene (USEPA, 2012c). The oral slope factor was developed from inhalation data

because the only available oral bioassay had several limitations for extrapolating to lifetime risk

in humans. Route- to -route extrapolation from the inhalation point of departures (PODs)

developed from the JISA study was carried out using the harmonized physiologically based

pharmacokinetic (PBPK) model.

Criteria Derivation- Analysis

Table 1 summarizes model inputs used to derive the 2014 updated human health

ambient water quality criteria for tetrachloroethylene. Criteria calculations are presented

below. These updated tetrachloroethylene criteria recommendations are based on the 2000

Methodology and updated exposure assumptions as described above (Exposure Factors).

7Tetrachloroethylene 127

- 18 -4

Table 1. Summary of input parameters for 2014 human health ambient water quality criteria

for tetrachloroethylene

Component Value Source Input Characterization

CSF 0.002 per mg/kg·day USEPA,

2012c an upper bound, approximating a 95%

confidence limit, on the increased cancer risk

from a lifetime exposure to an agent by

ingestion

BW 80 kg USEPA,

2011 ΢̯͋Σ Ϯ͋Ίͽ·χ ͕Ϊι ̯͇ϢΜχν (≥21 Θ̯͋ιν Ϊ͕ ̯ͽ͋)

DI 3 L/day USEPA,

2011 90 th ζ͋ι̽͋ΣχΊΜ͋ ͕Ϊι ̯͇ϢΜχν (≥21 Θ̯͋ιν Ϊ͕ ̯ͽ͋)

FCR TL2 0.00 8 kg/day

USEPA

, 2014 90 th percentile consumption rate for the U.S.

̯͇ϢΜχ ζΪζϢΜ̯χΊΪΣ (≥21 Θ̯͋ιν Ϊ͕ ̯ͽ͋) TL3 0.00 9 kg/day

TL4 0.00 5 kg/day

BAF TL2 54.22 L/kg

USEPA,

2012a EPI Suite K OW model estimated steady

- state

BAF values for non

- ionic organic chemicals in 3

general trophic levels of fish in temperate

environments (10°C) TL3 52.97 L/kg

TL4 46.04 L/kg

For consumption of water and organisms:

= / AWQC (μg/L) = [10 -6 / CSF (kg·d/mg)] × BW (kg) × 1000 (μg/mg)

4 DI (L/d) + ∑ (F· Ί (Ιͽ ͇) ∓ !F Ί (ͫ Ιͽ)) Ί 2

= 10 -6 / 0.002 kg·d/mg × 80 kg × 1000 μg/mg

3 L/d + ((0.008 kg/d × 54.22 L/kg) + (0.009 kg/d × 52.97 L/kg) + (0.005 kg/d × 46.04 L/kg))

= 9.660 μg/L (rounded to 10 μg/L because of significant figures, see 2000 Methodology)

For consumption of organisms only:

= / / AWQC (μg/L) = [10 -6 / CSF (kg·d/mg)] × BW (kg) × 1000 (μg/mg)

4 ∑ (F· Ί (Ιͽ ͇) ∓ !F Ί (ͫ Ιͽ))

Ί 2

= 10 -6 / 0.002 kg·d/mg × 80 kg × 1000 μg/mg

(0.008 kg/d × 54.22 L/kg) + (0.009 kg/d × 52.97 L/kg) + (0.005 kg/d × 46.04 L/kg)

= 35

. 066 μg/L (rounded to 40 μg/L because of significant figures, see 2000 Methodology)

The updated magnitude of the human health ambient water quality criteria for

tetrachloroethylene at the 10 -6 risk level are 10 μg/L (water and organism) and 40 μg/L

(organism only) (Table 2). These updated criteria replace the previously published values

(USEPA, 2002b ).

8Tetrachloroethylene 127

- 18 -4

Table 2. ΋Ϣ΢΢̯ιΘ Ϊ͕ E ́!͛ν ζι͋̽ΊΪϢνΜΘ ι͋̽Ϊ΢΢͋Σ͇͇͋ ( 2002) and updated (2014) human health

ambient water quality criteria for tetrachloroethylene

2002 Human Health AWQC 2014 Human Health AWQC

Water and Organism 0.69 μg/L 10 μg/L

Organism Only 3.3 μg/L 40 μg/L

These AWQC are meant to be protective of human health for the general adult

population from an increased cancer risk due to exposure to tetrachloroethylene at a 10 -6 or 1

in 1,000,000 risk level. The 10 -6 risk level associated with the AWQC represents the

̽ΪΣ̽͋Σχι̯χΊΪΣ χ·̯χ ϮΪϢΜ͇ ̼͋ ͋ϳζ͋̽χ͇͋ χΪ ΊΣ̽ι̯͋ν͋ ̯Σ ΊΣ͇ΊϭΊ͇Ϣ̯Μ͛ν ΜΊ͕͋χΊ΢͋ ̯̽Σ̽͋ι ιΊνΙ ͕ιΪ΢

exposure to the particular pollutant by no more than one chance in one million, regardless of

the additional lifetime cancer risk due to exposure, if any, to that particular substance from

other sources.

Criteria Characterization

The updated 2014 human health AWQC for tetrachloroethylene take into account

current data on health effects and exposure input parameters, consistent with the 2000

Methodology. The update d 2014 human health AWQC for tetrachloroethylene are between

one and two orders of magnitude greater χ·̯Σ E ́!͛ν ζι͋ϭΊΪϢνΜΘ ι͋̽Ϊ΢΢͋Σ͇͇͋ 2002 criteria;

i.e. the water-and-organism criterion increased from 0.69 to 10 μg/L and the organism-only

criterion increased from 3.3 to 40 μg/L (Table 2). The following paragraphs describe the

individual influence of each of the revised model inputs and exposure assumptions on the

overall change in value.

Body Weight

E ́!͛ν Ϣζ͇̯χ͇͋ AWQC assume a higher body weight compared to the previously

recommended 2002 criteria, reflecting a recent rise in average adult body weight among the

U.S. population. The updated body weight assumption of 80 kg based on recent survey data

from the 1999

− 2006 NHANES data is 10 kg greater than the previous recommendation of 70 kg.

Assuming all other input parameters remain constant, a higher average body weight in the

AWQC calculations (Eq. 1 and 2 above) results in higher AWQC. That is, as body weight

increases, the level of a contaminant in water at or below which negative health effects are not

anticipated from a lifetime of exposure also increases.

Drinking Water Intake

The updated drinking water intake assumption is 3 L/day, which is higher than the

previously recommended rate of 2 L/day. Assuming all other input parameters remain constant,

a higher drinking water intake assumption in the AWQC calculations (Eq. 1 and 2 above) results

in lower AWQC. That is, as drinking water intake increases, and thus overall exposure increases,

the level of a contaminant in water at or below which negative health effects are not

anticipated from a lifetime of exposure decreases.

9Tetrachloroethylene 127

- 18 -4

Fish Consumption Rate

The updated fish consumption rate is 22 g/day, divided into trophic level rates of 8

g/day, 9 g/day, and 5 g/day for trophic levels 2, 3, and 4, respectively, which is higher than the

previously recommended rate of 17.5 g/day. Assuming all other input parameters remain

constant, a higher fish consumption rate assumption in the AWQC calculations (Eq. 1 and 2

above) results in lower AWQC. That is, as fish consumption increase, and thus overall exposure

increases, the level of a contaminant in water at or below which negative health effects are no t

anticipated from a lifetime of exposure decreases.

Bioaccumulation Factor

The updated AWQC rely on EPI Suite model-estimated BAFs rather than the previously

recommended BCF of 30.6 L/kg. The lower (TL2), mid (TL3), and upper (TL4) trophic level BAFs

as sumed in the updated criteria equations (Eq. 1 and 2 above) are 54.22, 52.97, and 46.04 L/kg

wet-weight, respectively. Assuming all other input parameters remain constant, the higher

ratios of fish tissue concentrations to water concentrations of tetrachloroethylene by aquatic

organisms result in lower AWQC. That is, as bioaccumulation or bioconcentration of a

contaminant in fish and shellfish increases, and thus overall exposure increases, the level of a

contaminant in water at or below which negative health effects are not anticipated from a

lifetime of exposure decreases. The utilization of a bioaccumulation factor rather than a

bioconcentration factor better represents the amount of a contaminant accumulating in an

organism because it accounts n Ϊχ ΪΣΜΘ ͕Ϊι χ·͋ Ϊιͽ̯ΣΊν΢͛ν ͋ϳζΪνϢι͋ χΪ χ·͋ ζΪΜΜϢχ̯Σχ ΊΣ χ·͋ Ϯ̯χ͋ι

column, but also from the food chain and surrounding environment as well as

biotransformation of the pollutant in the organism due to metabolic processes. The utilization

of the three trophic levels of fish and shellfish consumed, as opposed to representing all trophic

levels of fish and shellfish consumed by a single value, allows for better exposure

representation, especially when pollutants bioaccumulate in significantly different amounts for

organisms in different trophic levels at different positions in the food chain.

Cancer Slope Factor

The updated CSF of 2 × 10 – 3 per mg/kg·day replaces the higher value of 3.98 × 10 – 2 per mg/kg·day. The change in the CSF was due to new available study data (USEPA, 2012c).

Assuming all other input parameters remain constant, a lower CSF in the AWQC calculations

(Eq. 1 and 2 above) results in higher AWQC. That is, as the CSF decreases, the level of a

contaminant in water at or below which the number of individuals at a specified risk level of

developing cancer above the background rate increases.

Additional routes of exposure to a particular pollutant besides exposure from water

intake and fish consumption are possible and may be considered when setting criteria for a

state or tribe. Possible additional routes include, but are not limited to, dermal exposure,

inhalation exposure, marine fish and shellfish consumption (when not included in the fish

consumption rate), and non-fish dietary exposures (fruits, vegetables, grains, meats or poultry).

10Tetrachloroethylene 127

- 18 -4

If scientific evidence exists which indicate that one or more of these routes pose a significant

risk of exposure, states and authorized tribes are encouraged to ensure that subpopulations are

adequately protected.

States, territories, and authorized tribes have the flexibility to develop criteria, on a sitespecific basis, that provide additional protection appropriate for highly exposed populations.

EPA is aware that exposure patterns in general, and fish consumption in particular, vary

substantially. EPA understands that highly exposed populations may be widely distributed

geographically throughout a given state, territory, or authorized tribal area. EPA recommends

that priority be given to identifying and adequately protecting the most highly exposed

populations. Thus, if a state, territory, or authorized tribe determines that a highly exposed

population is at greater risk and would not be adequately protected by criteria based on the

ge neral population, and by the national 304(a) criteria in particular, the state, territory, or

authorized tribe may adopt more stringent criteria using alternative exposure assumptions

(USEPA, 2000). Subpopulations that may be considered include, but are not limited to,

recreational fishers, subsistence fishers, women of childbearing age, and children. When

scientific data exist showing one of these subpopulations is at risk of greater exposure to the

pollutant or are biologically more sensitive, then the relevant inputs should be considered in

setting criteria. This could entail raising the fish consumption rate to a level more reflective of

the subpopulation based on collected data or adjusting the body weight and drinking water

intake.

Chemical Name / Synonyms

 Tetrachloroethylene (CAS Number 127- 18

- 4)

 Ankilostin

 Antisal 1

 Antisol 1

 Carbon bichloride

 Carbon dichloride

 Czterochloroetylen

 Dee-Solv

 Didakene

 Didokene

 Dowclene EC

 Dow-Per

 ENT 1,860

 Ethene, tetrachloro­

 Ethylene tetrachloride

 Ethylene, tetrachloro­

 Fedal- Un

 NCI-C04580

 Nema

11Tetrachloroethylene 127

- 18 -4

 PCE

 PER

 Perawin

 PERC

 Perchloorethyleen, per

 Perchlor

 Perchloraethylen, per

 Perchlorethylene

 Perchlorethylene, per

 Perchloroethylene

 Perclene

 Percloroetilene

 Percosolv

 Percosolve

 PERK

 Perklone

 Persec

 Tetlen

 Tetracap

 Tetrachlooretheen

 Tetrachloraethen

 Tetrachloroethene

 Tetrachloroethylene

 1,1,2,2-Tetrachloroethylene.

 Tetracloroetene

 Tetraguer

 Tetraleno

 Tetralex

 Tetravec

 Tetroguer

 Tetropil

References

JISA (Japan Industrial Safety Association). 1993. Carcinogenicity study of tetrachloroethylene by

inhalation in rats and mice. Hadano, Japan.

USEPA (U.S. Environmental Protection Agency). 1980. Ambient Water Quality Criteria for

Tetrachloroethylenes. Office of Water. Washington, DC. EPA-440-5- 80 -073.

http://water.epa.gov/scitech/swguidance/standards/criteria/upload/AWQC-forTetrachloroethylene_1980.pdf

.

12Tetrachloroethylene 127

- 18 -4

USEPA (U.S. Environmental Protection Agency). 2000. Methodology for Deriving Ambient Water

Quality Criteria for the Protection of Human Health. Office of Water. Washington, DC.

EPA- 822 -B- 00

- 004.

http://water.epa.gov/scitech/swguidance/standards/upload/2005_05_06_criteria_hum

anhealth_method_complete.pdf

.

USEPA (U.S. Environmental Protection Agency). 2002a. Estimated Per Capita Fish Consumption

in the United States. Washington, DC. EPA- 821 -C- 02 -003.

http://water.epa.gov/scitech/swguidance/standards/criteria/health/upload/consumpti

on_report.pdf

.

USEPA (U.S. Environmental Protection Agency). 2002b. National Recommended Water Quality

Criteria: 2002. Office of Water. Washington, DC. EPA- 822 -R- 02 -047.

http://water.epa.gov/scitech/swguidance/standards/upload/2008_04_29_criteria_wqct

able_nrwqc-2002.pdf

.

USEPA (U.S. Environmental Protection Agency). 2005. Guidelines for Carcinogen Risk

Assessment. Washington, DC. EPA- 630 -P- 03 -001F.

http://www.epa.gov/raf/publications/pdfs/CANCER_GUIDELINES_FINAL_3- 25 -05.PDF

.

USEPA (U.S. Environmental Protection Agency). 2011. Exposure Factors Handbook: 2011

Edition. Office of Research and Development. Washington, DC. EPA-600-R- 09 -052F.

http://www.epa.gov/ncea/efh/pdfs/efh-complete.pdf

.

USEPA (U.S. Environmental Protection Agency). 2012̯ ̈́ EνχΊ΢̯χΊΪΣ  ́ιΪͽι̯΢ν ͜Σχ͋ι͕̯̽͋ ΋ϢΊχ͋TM

for Microsoft® Windows, v 4.10. United States Environmental Protection Agency,

Washington, DC, USA. http://www.epa.gov/oppt/exposure/pubs/episuite.htm

.

USEPA (U.S. Environmental Protection Agency). 201 2b

. Framework for Human Health Risk

Assessment to Inform Decision Making

. Office of the Science Advisor. Washington, DC.

EPA- 601 -D- 12 -001. http://www.epa.gov/raf/files/framework-document-7- 13 -12.pdf

.

USEPA (U.S. Environmental Protection Agency). 2012c. Toxicological Review of

Tetrachloroethylene (Perchloroethylene). Washington, DC. EPA- 635 -R- 08 -011F.

http://www.epa.gov/iris/toxreviews/0106tr.pdf

.

USEPA (U.S. Environmental Protection Agency). 2014. Estimated Fish Consumption Rates for

the U.S. Population and Selected Subpopulations (NHANES 2003-2010). Office of Water.

Washington, DC. EPA- 820 -R- 14

- 002.

13